Mounting for surveyor&#39;s targets



June 17, 1941. I CHASKIN 2,245,901

MOUNTING FOR SURVEYORS TARGETS Filed Sept. 26, 1959 1 /W INVENTOR.jihraZzZ 671 f /J/iflib' A ATTORNEY Patented June 17, 1941 UNH'EEDSTATES PATENT GFFICE 2,245,901 MOUNTING FOR SURVEYORS TARGETS HaroldChaskin, New York, N. Y.

Application September 26, 1939, Serial No. 296,561

1 Claim.

This invention relates to a target used in surveying, especially incities, and has for its object to provide an improved target capable ofbeing correctly positioned in a shorttime and with little effort.

Another object has been to provide a target mounting so that severalmeasuring or transit parties may work toward or away from it at the sametime.

In surveying in urban centers for piping, subways, and a multitude ofpurposes, it has been often the practice to use a rigid target mountedon a tripod but positioned over some precise mark on the ground by meansof a plumb-line. On windy days it is difiicult to get the plumb exactlyin position. Sometimes several men have had to stand around theplumb-line with their coats open in an effort to shield it from thewind. Under this invention these disadvantages have been eliminated.

Referring to the drawing- Fig. 1 shows one embodiment of this invention.

Fig. 2 is a detail of the supporting rod which is held by the tripod.

Fig. 3 shows the top of the tripod.

Some conventional type target I is supported on the rigid rod II whichhas a lower extension portion i2 reaching to adjacent a mark l3 on theground over which the target is to be accurately alined. The legs of thetripod M are of conventional form and support the target and its rod II.The lower end I6 of the rod H is separable and pointed as shown in Fig.2 to facilitate correctly and quickly placing the pointed end over themark it. The portion [1 of the rod which is clamped by the top of thetripod is knurled or otherwise suitably roughened to enable the rod tobe securely held. A level I is preferably afiixed to the rod and securedby the screw threads [8 shown at the end of the separable portioncontaining the level. This level is of a well known type usuallycircular so that the bubble when in the center indicates that the rod towhich it is attached is vertical.

Another target I9 may be located either above or below the first targetand is supported so as to be displaced at any desired angle in such aposition so that one or more measuring or transit parties may worktoward or from each target. As shown in Fig. 1 the second target if! islocated at right angles to the first target. It will be understood thatmore than two targets may be used and any one of them may be located atany desired horizontal angle with respect to another and held in suchdesired position preferably by means of a clamp and wing nut not shownthough, of course, if desired a good friction fit may suffice instead.

As shown in Fig. 3 the legs M of the tripod are connected to a head 29which carries an upstanding threaded flange 2| as is customary fortripods used to support a transit, level and other instruments. Screwedover the flange 2| is a base 22 of the removable support for the rod II.

This support comprises a tubular guide portion 23 through which the tubeis movable with a sliding fit so that the pointed end I6 may be broughtclosely over the ground mark l3 regardless of the height of this mark orthe height of the tripod. A clamp 24 holds the rod l I securelysupported in the tubular guide. This clamp is provided with a customarywing nut 25 or other suitable means for loosening or tightening theclamp. Leveling screws 26, preferably four in number as is usual, areprovided between extensions from the tubular guide 23 and the base 22 ofthe removable support, so that the tubular guide may be leveledirrespective of whether or not the base 22 is level. Between the baseportion 22 and the tubular guide .23 is a connection 21 which allowslimited tilting of the tubular guide with respect to the base and alsoallows limited horizontal motion in any direction between the guide 23and the base portion 22, so that the lower end iii of the rod may beshifted in a horizontal plane to bring it directly over the ground markI3.

Among the advantages of this invention maybe mentioned the ease ofsetting up the target over a mark on a windy day. The lateralprojections shown for the tubular guide 23 may or may not be providedwith bubble tubes arranged at right angles to one another to assist inleveling. In other words, the leveling may be done entirely by means ofthe level [5, or the additional level tubes referred to may be used, orsuch additional tubes may take the place of and render the level l5unnecessary especially when the rod has a fairly snug fit within thetubular guide 23. The removable support for the target rod difiers fromthe removable support ordinarily attached to a tripod by reason of thecentral hole through which the rigid rod I l projects.

I claim:

The combination with a tripod having a head, of a surveyors target, arod on which the target is carried, a support carried by said head forsaid rod, an alined rigid axial projection of said rod having a pointedend extending below said support to adjacent the ground for cooperationwith a marker on the ground, said head having a perforation thereinthrough which said rod projection passes, and means located between saidhead and support for adjusting said rod, projection, and target intovertical position above said marker.

HAROLD CHASKIN.

